摘要
本研究通过对规模化牧场测定日数据进行分析,旨在估计不同地区305 d校正产奶量对应泌乳天数(DIM)的校正系数与胎次校正系数。利用Wood(不完全伽玛)模型对来自不同温度带9个参考群11749头荷斯坦奶牛2010-2020年间的683160条测定日产奶量拟合泌乳曲线,估计泌乳曲线参数,计算头胎牛和经产牛1~305 d泌乳天数对应的校正系数,分别分析参考群和验证群305 d校正产奶量和305 d实际累积奶量的差异;利用SAS 9.2中混合线性模型对1~6胎至少有前5个胎记录的牛估计305 d奶量的胎次效应值,并计算1~6胎各胎次的乘法校正系数;比较传统系数和新系数校正结果的差异。结果表明:①参考群头胎牛和经产牛中,泌乳曲线方程的拟合度R^(2)范围分别为0.4593~0.4913和0.5796~0.6341,泌乳高峰日分别为79~85和53 d,泌乳高峰奶量分别为33.1~34.4和46.0~48.6 kg;②对于参考群,头胎牛和经产牛校正系数分别在泌乳≥90 d和泌乳≥30 d基本趋于一致,头胎牛和经产牛泌乳≥60 d的305 d校正产奶量均趋近于305 d实际累积奶量,奶量差值分别在100和200 kg以内;③对于验证群的305 d校正产奶量,头胎牛泌乳≥150 d和经产牛泌乳≥180 d的泌乳天数校正系数适用性更佳,305 d校正产奶量与305 d实际累积奶量比值高于79%;④1~6胎的胎次校正系数分别为1.2121、1.0380、1.0063、1.0000、1.0220和1.0290;⑤与传统系数相比,新泌乳天数校正系数校正效果更好,头胎牛和经产牛新系数校正的305 d奶量较305 d实际累积奶量相差分别在900和700 kg以内;利用新胎次校正系数,2~4胎产奶量可较为准确地校正到5胎成年当量。本研究结果表明,定期更新305 d校正产奶量的泌乳天数与胎次校正系数,便于准确地将不同泌乳天数、不同胎次状态下泌乳牛的产奶量调整到同一基准上,从而更好地比较奶牛个体泌乳性能的高低,为牧场管理提供参考依据。
The purpose of this study was to estimate the correction coefficient and parity adjustment coefficient of standardized 305-day milk yield corresponding to days in milk(DIM)in different regions,by analyzing the test-day data from scaled dairy farms.Wood model(Incomplete Gamma Function)was used to fit the lactation curves of 683160 test-day milk yield records from 11749 Holstein dairy cows from 9 reference population in different temperature zones in China from 2010 to 2020.The parameters of lactation curve were estimated,and the correction coefficients corresponding to the lactation days from 1 to 305 days of primiparous and multiparous cows were calculated.The differences between the standardized 305-day milk yield and actual accumulated milk yield at 305 days of reference group and validation group were analyzed respectively.Mixed linear model in SAS 9.2 was used to estimate the parity effects for cows with at least the first five lactations standardized 305-day milk yield of 1-6 parities,and the multiplicative adjustment coefficients of 1-6 parities were calculated.The difference between the conventional adjustment coefficient and new adjustment coefficient were compared.The results showed that:①For primiparous and multiparous cows of reference population,the goodness of fit(R^(2))ranges of lactation curve equation were 0.4593 to 0.4913 and 0.5796 to 0.6341,respectively.The peak days of lactation were 79 to 85 and 53 d,the peak milk yield was 33.1 to 34.4 and 46.0 to 48.6 kg,respectively.②In the reference population,the adjustment coefficients were basically consistent when DIM more than 90 d of primiparous and DIM more than 30 d of multiparous cows.Standardized 305-day milk yield for DIM more than 60 d was close to the actual accumulated 305-day milk yield,the difference of milk yield was lower than 100 and 200 kg,for primiparous and multiparous cows,respectively.③For the standardized 305-day milk yield of validation population,adjustment coefficients of DIM more than 150 d of primiparous and DIM more th
作者
徐伟
董飞
马志愤
亓建刚
常瑶
陈少侃
姜兴刚
王雅春
XU Wei;DONG Fei;MA Zhifen;QI Jiangang;CHANG Yao;CHEN Shaokan;JIANG Xinggang;WANG Yachun(EYIMU Science and Technology(Beijing)Co.,Ltd.,Beijing 100016,China;Institute of Animal Sciences,Chinese Academy of Agricultural Sciences,Beijing 100193,China;Sano(Yangling)Modern Animal Nutrition Co.,Ltd.,Xianyang 712100,China;College of Animal Science and Technology,China Agricultural University,Beijing 100193,China;Beijing Sunlon Animal Husbandary Develpoment Co.,Ltd.,Beijing 100029,China;Branch of Animal Husbandry and Veterinary of Heilongjiang Academy of AgriculturalSciences,Tsitsihar 161005,China)
出处
《中国畜牧兽医》
CAS
北大核心
2021年第12期4554-4566,共13页
China Animal Husbandry & Veterinary Medicine
基金
国家现代农业产业技术体系
长江学者和创新团队发展计划(IRT_15R62)
农业品种改良提升专项(2130135)。
